<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css</title>
    <!--外部样式-->
    <link rel="stylesheet" href="css库.css">
    <style>
    /*内部样式,元素选择器*/
        div{color: red}
    /*类选择器*/
        .class{color: black}
        #idnum{color: gray}
     /* 通用选择器
    {
        background-color: aqua;
    }*/
    /*属性选择器*/
        [size]{color: green}
    p[size]{color: aqua}
    p[size="4"]{color: salmon}
        /*伪类选择器*/
    a{text-decoration: none}
        a:link{color: brown}
        a:visited{color: tomato}
        a:hover{color: chartreuse}
        a:active{color: darkblue}
        /*后代选择器*/
        ol li{color: deeppink}
        /*组合选择器*/
    span,b{color: indigo}
    </style>
</head>
<body>
<div >
    red
</div>
<!--内联样式-->
<div style="color: blue">
    blue
</div>
<div  class="class" >
    black
</div>
<div  id="idnum">
    gray
</div>
<div>
    <font size="5">green</font>
</div>
<div>
    <p size="6">aqua</p>
</div>
<div>
    <p size="4">salmon</p>
</div>
<a href="#" >color</a>
<div>
    <ol>
        <li>deeppink</li>
    </ol>
</div>
<span>indigo</span>
<br/>
<b>indigo</b>
</body>
</html>